Preserving original doctype and declaration of an lxml.etree parsed xml

Question

I\'m using python\'s lxml and I\'m trying to read an xml document, modify and write it back but the original doctype and xml declaration disappears. I\'m wondering if there\

Answer 1

You can also preserve DOCTYPE and the XML declaration with fromstring():

import sys
from StringIO import StringIO
from lxml import etree

xml = r'''


 
 
 
 
 
This is an example
 
'''

tree = etree.fromstring(xml).getroottree() # or etree.parse(file)
tree.write(sys.stdout, xml_declaration=True, encoding=tree.docinfo.encoding)

Output

 
 
 
 
 
This is an example
 

Note the xml declaration (with correct encoding) and doctype are present. It even (possibly incorrectly) uses ' instead of " in the xml declaration and adds Content-Type to the .

For the @John Keyes' example input it produces the same results as etree.tostring() in the answer.